Mercury-vapor apparatus.



P. H. THOMAS.

MERCURY VAPOR APPARATUS. APPLICATION FILED JULY 20.19%5.

1,235,741 PatentedAug. 7,1917.

mi s/v TOR WITNESSES WM? j-( 2 4 II? By uric PERCY H. THOMAS, OF UPPER MQIITCLAIB, NEW JERSEY, ASSIGNOR 'TG CQOPER HEWITT ELECTRIC COMPANY. OF HOBOKEIN, NEW JERSEY, A CQRPORATXON 0F NEW ERSEY.

MEBCURY-VAPQE APPAEATU$..

memes.

To IZZ wlunvz it may concern:

Be it known that l, PERCY H. THOMAS, citizen of the United States, and resident of Uppe1'.Montclair, county of Essex, State of New Jersey, have invented certain new and useful Improvements in Mercury-Vapor Apparatus, of which the following is a specific cation.

My invention relates to the operation of mercury vapor lamps and especially to such lamps when operated at relatively high pres sures, from score-es supplying alternating current. ,My invention further aims to provide means making it possible to operate such alemp or other apparatus by passing current from the source in opposite directions between the sameelectrode's. When mercury vapor lamps are operated from alternating mainsat relatively low pressures it is usuully more convenient to provide an extra anode and pass the current alternately from the two anodes to the same cathode. However, is the method of operation here set forth it is possible to operate from an alternating supply directly with only two elec' tro r e mercury vapor lamp has a very high resistance to starting; but when the tampon ature of the electrodes, assuming these to be of mercury is raised suihciently, this starting resistance is much lowoiyed and a lamp that will not run on a certain voltage cold will operate satisfactorily on this voltagewhcn its temperature is sufficiently high. I. overcome the difficulty of getting the lamp heated to the point at which it will operate on normal alternating voltage by various methods, such as raising the alternating voltage at the start, shortening the vapor path at the start, or preheating the mercury before attempting to start the fiow of cur rent in the vapor; I do non however, claim to be the first to preheat the mercury of a vapor lump broadly. The application of these arrangements will be ointed out in more detail in connection with the various figuresof the drawings.

It may be well to point out that the nor-- mal resistance to current flow in those mor cury vapor-devices depends as one "factor upon the pressure of the vapor which in turn depends upon the temperature of the mercury in the. container. The relation between the amount of heat generated in the mercury specification of Letters Yateut.

and this applic tion filed July 20,

by the operation and the natural rate of heat dissipation of heat from the r'nercury is the Iuctor determining the normal temperature of the n'zercury and the various parts and current strengths may be proportioned in conformity therewith.

. It is furthermore well known that such apparatus operates most satisfactorily when there is some voltage absorbing device in series therewith or when it is ed by constant currents. V

In the drawings I show a system of circuits acla ted for any oi tlfe mercury vaggir devices 0' the usual typos. vv This lamp is preferably constructed/and exhausted as is usual for mercury vcpol lamps, that is by exhausting all gases from the container and the walls of the chamber. However, it will be found advantageous in some cases to facilitate the initial starting oy leaving 1, a certain amount of residual gases between the electrodes. The: presence oi such gas serves to lessen considerably the resistance of the device to the initiation of current flow. The container is hermetically sealed and when the gases have been eliminated as already described it i's'sealed from the pump. y r

l Vhcn current is thrown on the constant po ential-L main 1.,the transformer primary 2 ls'energized through the inductance device 3,"the resistance 4, the conductor 5 and tho .forxner, whose core 8 is provided with a shunt leakage path, having an open magnetic circuit. These two coils operating together, produce in effect an inductance device in series with the circuit which operates as steadying means. ll/here desired, a very high potential can thus be impressed upon the device 15 during the, starting period only, without maintaining such high potential during operation.

While I have described my invention with regard to the specific diagram and figure Patenteunug. 1,1917.

(iii

' be properly illustrated, I do not Wish to limit myself to the particular embodiment of my invention but consider any system utilizing the novel features of this disclosure to come Within. my invention.

The lamp structure shown may, if desired, be made of quartz many of the other usual materials for these devices may be used over a wide range of pressure. 01 course, in each case the pressure of the vapor, the 'dimensions of the tube, the voltage impressed and radiating power, of the apparatus must correlated to secure the results described.

Many of the lamps shown may be open ated to advantage upon direct current, but in this application I have illustrated more particularly, alternating current sources. Material other than mercury may be used in these tubes and when run at a high temperature any material, even material solid at the temperature appropriate to low pressure lamps may be used as the electrode insterial. I may mention tin, which has a very low vapor pressure; zinc and copper as'materials that may become liquid at reasonable temperatures, each giving' its own characteristic color; also lead, lithium; and cadmium.

This application is a division of my application Serial N umber 719,924, filed September 12th, 1912.

I claim as my invention:

1. In a system of electrical distribution, the combination with alternating current constant potential mains, an apparatus rcq uiring at high starting and a low operating voltage and voltage-absorbing steadying means, and a transformer having a separated primary and secondary, both in series With the lamp,

eann-n and a shunt circuit energizing said primary winding across the mains during the starting period only.

The combination of alternating mains, a consumption. device in series with a. trans former winding across said mains, means for shunting said device and a part of said Winding and means responsive to the starting of normal operation for interrupting 'sald shunt.

3. The coinbinntionof alternating current inains, a consumption device, a transformer binding connected in series therewith across said mains, a shunt circuit across said mains including a portion of said transformer Winding and current controlling means in said shunt.

s. The combination of alternating current n ains, a consumption device, a transformer winding connected in series therewith across said mains, a shunt circuit across said mains including a portion of said transformer winding and current controlling means in said shunt and meats responsive to current in said. device for interrupting said shunt circuit.

5. In combination, a primary transformer .vindin a secondary therefor a. connection b7 i 7 between said primary and said secondary, a. circuit including said primary and sold secondary and separate means for supplying- 

